1. Field of the Invention
The present invention relates generally to a fiber optic gyroscope, and specifically to an improved dressing for the leads of a fiber optic gyroscope sensing coil.
2. Description of Related Art
Fiber optic gyroscopes are used to measure the rate of rotation of a particular vehicle or platform. In order to measure the rotation of a fiber optic gyroscope, often counter-propagating waves are input through fiber optic leads attached to a fiber optic sensing coil. A phase shift between the counter-propagating waves develops as a result of the rotation of the fiber optic sensing coil. The fiber optic leads extend from the fiber optic sensing coil to a device, such as an integrated optics chip, for measuring the relative phase difference between the waves.
There have been various dressing techniques attempted in the past for attaching the fiber optic leads to the fiber optic sensing coil. Usually, these dressing techniques have included some form of bonding, such as the use of adhesive tape or transfer adhesive. These prior bonding techniques generally either failed to provide enough support for the leads or used an adhesive having too high of a modulus of elasticity, which can cause strain-induced bias errors in the gyroscope output. It is often necessary to remove the fiber optic leads from their attachment to the fiber optic sensing coil to perform troubleshooting. When a defect occurs in the fiber optic leads or the fiber optic sensing coil, the bond between leads and the fiber optic sensing coil needs to be broken so that the fiber optic leads can be removed and reworked. An adhesive having too high of a modulus of elasticity precludes removal of the fiber optic leads without damage to the jacket of the leads or to the sensing coil fiber.
Further, various environmental conditions and vibrations confronted by the fiber optic sensing coil over time impute a stress on the fiber optic leads. When a high modulus adhesive is used to affix the fiber optic leads to the sensing coil, the leads are rigidly retained against the sensing coil and prevented from moving relative to the sensing coil. Any imputed stress on the sensing coil structure is then exerted on the leads themselves. This stress on the leads causes their shape to distort, where even the slightest deviation in shape affects the wavelength propagation characteristics of the fiber optic leads.
Clearly, there is a need for an improved dressing for the fiber optic leads of a fiber optic gyroscope sensing coil which allows the fiber optic gyroscope to function consistently over a variety of environmental conditions. Moreover, there is a need or an improved dressing for the fiber optic leads of a fiber optic gyroscope sensing coil which stably retains the fiber optic leads in position against the fiber optic sensing coil while allowing the fiber optic leads to be repeatedly reworked without damaging either the leads or the sensing coil.